Method of making shafts having sheet metal journal surfaces



Sept. 6, 1949. H, KOCH 2,481,025

METHOD OF MAKING SHAFTS HAVING SHEET METAL JOURNAL SURFACES Filed D60.15, 1945 INVENTOR Gusnv M-Kacu ATTORNEY wn massss:

Patented Sept. 6, 1949 METHOD OF MAKING SHAFTS HAVING SHEET METALJOURNAL SURFACES Gustav H. Koch, Springfield, Mass., assignor toWestinghouse Electric Corporation, East Pittsburgh, Pa., a corporationof Pennsylvania Application December 15, 1945, Serial No. 635,327

1 4 Claims.

My invention relates to a method of making a shaft having a sheet metaljournal surface.

Heretofore, shafts which include a journal surface and also a crankportion have been made from two separate parts, one a die-cast crankmember and the other a steel shaft which is centerless ground and milledafter forming in a screw machine, the two parts being assembled togetherby riveting.

It is an object of my invention to provide a method of making a shafthaving a satisfactory journal surface, more particular objects being toprovide a method that may be carried out at low cost and to provide amethod that produces an accurate cylindrical journal surface.

In accordance with my invention, a liner, made of a suitable metal suchas steel and having a smooth surface, is provided to form the journalsurface and the remainder of the shaft, including the crankshaftportion, is cast into the steel liner. The pressure of the molten metalis utilized to force the steel liner outwardly against the accuratelyformed cylindrical bore of a die sleeve, thereby providing an accuratelyformed journal surface requiring no further machining or grinding.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in connection with theaccompanying drawings, forming a part of this application, in which:

Fig. 1 is a longitudinal section of a shaft made in accordance with myinvention;

Fig. 2 is an end view of the shaft;

Fig. 3 is a transverse section taken on line III-III of Fig. 1;

Fig. 4 is an end view of the shaft;

Figs. 5 and 6 are side and end views of the partly formed steel liner;

Fig. 7 is a perspective view of the liner in substantially final form;and

Fig. 8 is a sectional view showing the shaft and the die.

Referring to the drawing in detail, I show a shaft II] which, in thisinstance, is the oscillating shaft used in the oscillating mechanism ofan electric fan. The shaft includes a disc II at one end formed with arecess l2 and a slot I3, as clearly shown in Figs. 1 and 2. At theopposite end, the shaft includes a portion 19 which is square in crosssection.

The shaft is further provided with a cylindrical journal surface Hwhich, in accordance with the present invention, is formed by a steelliner I5.

. The liner I5 includes a cylindrical portion and two flanges l6 whichextend inwardly from the meeting edges of the cylindrical portion, asclearly shown in Figs. 3 and 7. The remainder of the shaft I0 is a diecasting, for example, a zinc die casting.

In making the shaft, polished steel shim stock is used to form the linerwhich provides the journal surface. The liner may have a thickness of,for example, .005 of an inch. The fiat shim stock, in rectangular formof suitable dimensions, is first bent to the form shown in Figs. 5 and6, including flanges l6, curved portions l7 and a fiat central portion[8. In bending the flanges IS, the distance between the lines alongwhich these flanges are bent is closely controlled so that the peripheryof the liner, as shown in Fig. 7, will be that of the desired journalsurface. It is then formed to the shape shown in Fig. 7, in which thecurved portions I7 and the flat portion 18 have been formed into acylindrical portion and in which the adjacent sides of the flanges l6bear against each other.

In the die casting operation, there is employed a die having anaccurately formed cylindrical bore. For example, a die as shown in Fig.8 may be used. This die comprises two die members 2| and 22 and a diesleeve 23 which has an accurately formed cylindrical bore 24 therein.The die member 22 includes parts 25 and 26 which form the recess l2 andthe slot l3. The die is also provided with a gate at any suitable point,for example, along the plane of division between the die members. InFig. 8, a gate 21 is shown at the top for clarity of illustration. Thesteel liner, after having been formed to the shape shown in Fig. 7, isinserted in the die sleeve 23. The initial tension or resilience holdsthe liner tightly against the surface of the die sleeve. The die sleeve23 is then positioned between the die members 2i and 22, as shown inFig. 8. The molten die casting metal, preferably zinc, is then admittedthrough the gate 21. It is admitted under high pressure, such as 500 to4000 pounds per square inch. As will be apparent from Fig. 7, the moltenmetal is admitted to the interior of the liner sleeve l5 and the highpressure thereof forces the liner firmly against the accurately formedcylindrical surface 24, thereby providing an accurately formedcylindrical journal surface. It is a characteristic of die-castingoperations of this character that the molten metal does not enter, toany appreciable extent, the slight crevices that may and usually doexist between the liner and the die sleeve, so that the pressure of themolten die-casting metal within the liner sleeve is effective to forcethe same against the cylindrical bore 24 of the die sleeve. When suchmolten metal starts into a small crevice between the liner and the diesleeve, it is chilled by such parts, which are at a temperature lowerthan the melting point of the molten metal, and thus the metal isprevented from flowing further intothe crevice.

After the casting operation is completed, the die members 2| and 22 areseparated and the die sleeve 23 and shaft are removed therefrom, theparts 25 and 26 being withdrawn from the recess 12 and the slot 13: Thedie sleeve 23 is withdrawn axially from the shaft.

There is thus produced a shaft which, except for the forming of theliner, is provided by" a; single casting operation. The forming of theliner into the proper shape may be effected by simple operations in apunch press. The flanges 16 are firmly anchored within the" die castingand thereby secure the liner firmly on the shaft.

While I have shown my invention in but one form, it will be obvious tothoseskilled inthe art that it is not so limited, but is susceptible" ofvarious changes and modifications without departing from the spiritthereof.

What I claim is:

1. The method of making a shaft having a cast-in, sheet metaljournal'surface, which moth od comprises forming a piece of sheet metalto form a cylinder and flanges extending inward-1y from meeting edges ofthe portion forming the cylinder, placing said sheet metal in the cylindrical bore portion of a die, delivering molten casting material underpressure into the interior of the cylindrical sheet metal, and forcingsaid sheet metal by such pressure against the cylin drical surface ofsaid die, thereby forming a shaft and an accurate cylindrical journaisurface thereon.

2. The method of making a shaft having a; cast-in sheet metal journalsurface, whichmethod comprises folding a. sheet metal to form acylinder, inserting said sheet metal into the cylindrical bore of a diehaving an accurately formed cylindrical bore, delivering molten castingmaterial under pressure into the cavity in said die 4 including theinterior ofsaid liner, and forcing the sheet metal by such pressureagainst the cylindrical surface of said die, thereby forming a shaft andan accurate cylindrical journal surface thereon.

3. The method of making a shaft having a cast-fir sheet metal journalsurface, which method comprises folding a sheet metal to form acylinder, inserting said sheet metal into the cylindrical bore portionof a die sleeve, placing said die sleeve between two die members,delivering molten casting material under pressure into the cavity formedby said die members including the interior of said liner, and forcingthe sheet metal by such pressure against the" cylindrical surface ofsaid die sleeve, thereby formingv a shaft and an accurate journalsurface thereon.

4a The method of making a shaft having a sheet metal journal surface,which method comprises folding a piece of sheet metal to'form a cylinderand flanges extending inwardly from meeting: edges of said cylinderdisposed parallel tothe axis of said cylinder in the cylindrical bore,placing said die sleeve between two die members, delivering moltencasting material under pressure into the cavity formed by the diemembers and into the interior ofthe cylindrical sheet metal, and forcingthe sheetmetal by such pressure againstthe surface of said cylindrical=bore, thereby forming. a shaftand are accurate cylindrical journalsurface thereom GUSTAV KOCH.

REFERENCES CITED The following references are of' record in the file ofthis" patent:

UNITED STATES PA'I'ENTS Date

